1. Field of the Invention
The present invention relates to a portable electronic key to be used, while being carried by a user, in order to start an engine by making wireless communication with a control device mounted in a vehicle and verifying an ID.
2. Description of Background Art
Japanese Patent Laid-open No. 2004-276760 and Japanese Patent Laid-open No. 2004-114860, for example, describe electronic key systems using wireless communication between an electronic key carried by a user and a control device mounted in an actual vehicle, in order to verify an ID and start an engine based on an operation request made by an authorized user.
Japanese Patent Laid-open No. 2004-276760 relates to an anti-theft device for a vehicle or the like. In particular, a configuration is disclosed, which is capable of simply permitting or prohibiting an operation of an engine at a place remote from the vehicle or the like without using a key, in which the key and a key cylinder are removed. In a technical concept of Japanese Patent Laid-open No. 2004-276760, specifically, a portable transmitter (an electronic key) is used in order to simply permit or prohibit the operation of the engine. The portable transmitter is composed of a battery serving as a power supply, and an unlock button which is operated by a driver and transmits an ID code to the vehicle, for example. The unlock button releases a locked state of a vehicle operation instrument such as a steering wheel. A lock button is operated by the driver and transmits, to the vehicle, an ID code for prohibiting the operation of the engine. A remote control unit shapes a waveform of a transmission signal from the unlock button or the lock button and then converts the transmission signal into a signal corresponding to the ID code, and a transmission circuit which transmits, to the vehicle, the signal converted by the remote control unit.
Japanese Patent Laid-open No. 2004-114860 relates to an electronic key system for a vehicle, and discloses a technical concept enabling a warning to be outputted when a user drops an electronic key while the vehicle is stopping and running, thereby attempting to minimize a probability of a loss of the electronic key, which is caused because the user has dropped the electronic key.
In particular, a portable transceiver (the electronic key) of Japanese Patent Laid-open No. 2004-114860 has a card shape as an outline thereof, and includes an IC chip built therein. Specifically, as shown in FIG. 7, a battery 1, a power supply circuit 2, a CPU 3, a receiving circuit 4, and a transmission circuit 5 are built in an inside of the portable transceiver. In this case, the power supply circuit 2 supplies power from the battery 1 to the receiving circuit 4, the transmission circuit 5, and the CPU 3. A signal is transmitted/received to/from a control circuit (not shown). In such a way, a steering wheel is locked and unlocked, an engine is started and stopped, a warning lamp is turned on and off, and so on. With regard to details of the electronic key and the control circuit, specific configurations, functions, and effects thereof are disclosed in Japanese Patent Laid-open No. 2004-114860.
As described above, it is premised that the electronic key is carried. Moreover, in principle, no limitations are imposed on a region where the electronic key is used. Hence, there is a case where the electronic key is used in waterskiing, a pleasure boat, and the like. In this case, there is a possibility that the electronic key is dropped and lost in water and snow owing to mishandling thereof by the user. Moreover, a case body of the conventional electronic key is composed of synthetic resin or the like. Accordingly, when an operator of the pleasure boat or the like suspends the electronic key on the naked skin, the operator sometimes feels uncomfortable since the case itself is hard. This is because the hard case directly abuts on the naked skin.
The present invention has been made in consideration of problems as described above. It is an object of the present invention to provide a portable electronic key, of which location is easily recognizable, for example, even if the electronic key concerned sinks in water owing to some causes, and which does not give a feeling of discomfort to a user even if abutting on the naked skin.